Branching junction boxes are typically used in the engine compartments of automobiles in order to connect electrical components. Typically, they comprise a busbar substrate which is housed within a casing, the casing consisting of an upper case and a lower case which are joined by a gasket. Conventionally, the casing has two or more male connectors which are used in order to form the electrical connection between two components. The connectors comprise a male cavity having male tab openings therein. Tabs from the busbar substrate extend through the male tab openings and into the male connector cavity in order to provide a point of connection for the electrical components.
In the conventional assembly process of a branching junction box, the lower case is positioned with a positioning tool and a chuck portion of an automated device inserts the busbar substrate therein. Both the first and the last busbar substrates have their male tabs aligned with the male tab openings of the male connector. This can cause a problem in that the tabs do not always align and damage can occur either to the tabs or to the lower or upper case in the area of the male connector.
In order to overcome this misalignment problem, positioning pins have been employed on the positioning tool and corresponding holes have been made in the lower case and the busbar substrate. Such a solution is described in Japanese Utility Model Examined Publication Number 7-33541 (Japanese Utility Model Laid-Open Publication Number 1-146716). In this Publication, it is taught that the two positioning pins and corresponding holes are disposed at diagonal corners. It has been found that, by employing positioning pins along with their respective positioning holes, the misalignment problem and damage to both the tabs and the casing of the junction box can be significantly reduced.
Although the positioning pin and respective positioning holes solve the problem of misalignment, they result in another problem; i.e., the positioning holes allow moisture and dirt to enter the casing. Branching junction boxes are normally mounted in the engine compartment of an automobile. The engine compartment is not a closed area and dirt and water from the front tires and from the road surface often enter the engine compartment and cover the electrical components. Also, moisture from condensation forms on the top of the junction box casing. The pilot holes that are in the casing, both in the upper casing and the lower casing, provide entrances for both dirt and water into the junction box. As can be appreciated, both the dirt and water in the junction box can cause short circuiting and/or damage to the electrical circuitry therein; hence, there is a need to prevent their ingress into the electrical components of the junction box while still employing the positioning pin and positioning holes in its assembly.